Oil-electricity control method for single-gear series-parallel hybrid electric vehicle

Abstract

The invention relates to the technical field of automobile hybrid control, in particular to an oil-electricity control method for a single-gear series-parallel hybrid automobile, which comprises the following steps of: dividing the electric quantity of a power battery of the automobile into a low electric quantity interval, a medium electric quantity interval, a medium-high electric quantity interval and a high electric quantity interval; driving conditions of the vehicle are divided into an accelerator stepping state and an accelerator loosening state; obtaining a plurality of vehicle speed intervals; acquiring the current running state of the vehicle; selecting a corresponding working mode according to the current electric quantity interval of the vehicle and the corresponding driving working condition, the vehicle speed interval and the running state in the current electric quantity interval, and determining the current energy distribution of the vehicle through the corresponding working mode; wherein the working modes comprise a pure electric mode, an engine direct drive power generation mode, an engine direct drive mode, a parallel connection mode, a series connection mode, an energy recovery mode and a non-energy recovery mode. The fuel economy can be guaranteed, the NVH of the whole vehicle is improved, and the driving experience of a user is improved.

Description

Technical Field

[0001] The present invention relates to the technical field of automobile hybrid-electric control, and more particularly to a method for controlling an oil-electric vehicle in a single-speed series-parallel hybrid vehicle. Background Art

[0002] A single-speed series-parallel hybrid vehicle combines the advantages of both series and parallel hybrid systems, using a hybrid transmission for power coupling. It features a simple and easy-to-control structure, high efficiency, and good fuel economy. Currently, a hybrid control system primarily relies on pure electric driving, which results in rapid battery consumption. This reduces battery power, leading to a decrease in drive motor power. When the vehicle requires high power, the engine must increase speed to maintain power, which can easily lead to noise, vibration, and harshness (NVH) issues, resulting in a poor driving experience. Another existing dual-motor hybrid control device uses a relatively high battery charge threshold to ensure dual motor operation and motor drive power. This can easily cause the engine to start at idle or low speed when the charge is high, resulting in a poor driving experience. Summary of the Invention

[0003] The purpose of the present invention is to overcome the shortcomings of the existing technology that automobiles are prone to NVH problems, and to provide a hybrid vehicle oil-electric control method for a single-speed series-parallel hybrid vehicle, which can ensure fuel economy, improve the NVH of the entire vehicle, and enhance the user's driving experience.

[0004] In order to solve the above technical problems, the technical solution adopted by the present invention is: A method for controlling the oil and electricity of a single-speed series-parallel hybrid vehicle is provided, comprising the following steps: S1. The vehicle's power battery capacity is divided into a low capacity range C1≤SOC<C2, a medium capacity range C2≤SOC<C3, a medium-high capacity range C3≤SOC<C4, and a high capacity range SOC≥C4; among which, C4 C3= C3 C2>C1; S2. Divide the vehicle's driving conditions into an accelerator-pressed state and an accelerator-released state; S3. The vehicle speed is divided into low speed V1, medium speed V2, and medium-high speed V3, and several speed intervals are obtained accordingly; among which, V3 V2>V2 V1; S4. Get the current running state of the vehicle; wherein the running state includes a uniform speed state and a non-uniform speed state; S5. Select a corresponding working mode based on the vehicle's current power range, the corresponding driving conditions, speed range and operating status within the power range, and determine the vehicle's current energy distribution through the corresponding working mode; wherein the working modes include: pure electric mode, engine direct drive power generation mode, engine direct drive mode, parallel mode, series mode, energy recovery mode, and non-energy recovery mode.

[0005] The present invention provides a hybrid-electric control method for a single-speed series-parallel hybrid vehicle, which sets multiple power ranges according to the different power levels of the power batteries. Different hybrid-electric control strategies are adopted for the corresponding vehicle speed ranges, whether the vehicle runs at a constant speed, and different driving conditions under different power ranges. This method can optimize the engine's NVH while ensuring fuel economy, improve the quietness and smoothness of the customer's ride, and provide a better driving experience.

[0006] Furthermore, the power system of the single-speed series-parallel hybrid vehicle includes: an engine, a hybrid transmission, a power battery, and wheels, wherein the hybrid transmission includes a P1 generator, a single-speed direct drive mechanism, and a P3 drive motor; the engine and the P1 generator are mechanically transmitted, and a clutch is connected between the engine and the single-speed direct drive mechanism, and the single-speed direct drive mechanism and the P3 drive motor are both mechanically transmitted to the wheels; the power battery is electrically connected to the P1 generator and the P3 drive motor, and the P3 drive motor is electrically connected to the P1 generator.

[0007] Furthermore, the pure electric mode is: the power battery outputs power to the P3 drive motor, and the P3 drive motor drives the wheels; the engine direct drive power generation mode is: part of the engine power drives the wheels through the single-speed direct drive mechanism, and part of the power drives the P1 generator to generate electricity, which is then input into the power battery; the engine direct drive mode is: the engine drives the wheels through the single-speed direct drive mechanism; the parallel mode is: the engine drives the wheels through the single-speed direct drive mechanism, and at the same time the power battery outputs power to the P3 drive motor, and the P3 drive motor also drives the wheels; the energy recovery mode is: when the vehicle is coasting or braking, the P3 drive motor generates electricity, which is then input into the power battery.

[0008] Furthermore, in step S5, when the power battery power is within the high power range: when the driving condition is the accelerator condition, the pure electric mode is selected; when the driving condition is the accelerator condition, the energy recovery mode or the non-energy recovery mode is selected; wherein: the high power range C4≤SOC<C5 is set; when the power battery power is within the high power range C4≤SOC<C5, the energy recovery mode is selected, otherwise the non-energy recovery mode is selected.

[0009] Furthermore, in step S5, when the power battery charge is in the medium and high charge range: when the driving condition is the accelerator release condition, the energy recovery mode is selected; when the driving condition is the accelerator step condition: when the vehicle speed is <V3, the pure electric mode is selected; when the vehicle speed is ≥V3, the engine direct drive mode or the parallel mode is selected, among which: when the vehicle is in a uniform speed state, the engine direct drive mode is selected, otherwise the parallel mode is selected.

[0010] Further, in step S5, when the power battery charge is in the medium charge range: when the driving condition is the accelerator release condition, the energy recovery mode is selected; when the driving condition is the accelerator step condition: when the vehicle speed is <V2, the pure electric mode is selected; when the vehicle speed is in the [V2, V3) speed range, the series mode is selected; when the vehicle speed is ≥V3, the engine direct drive mode or the parallel mode is selected, among which: when the vehicle is in a uniform speed state, the engine direct drive mode is selected, otherwise the parallel mode is selected.

[0011] Furthermore, in step S5, when the power battery is in the low power range: when the driving condition is the accelerator release condition, the energy recovery mode is selected; when the driving condition is the accelerator step condition: when the vehicle speed is <V1, the pure electric mode is selected; when the vehicle speed is in the [V1, V3) speed range, the series mode is selected; when the vehicle speed is ≥V3, the engine direct drive power generation mode or the parallel mode is selected, among which: when the vehicle is in a uniform speed state, the engine direct drive power generation mode is selected, otherwise the parallel mode is selected.

[0012] Furthermore, the series mode includes a first series mode and a second series mode. The first series mode is: the engine drives the P1 generator to generate electricity, the P1 generator is input to the P3 drive motor, and the P3 drive motor drives the wheels; the second series mode is: the engine drives the P1 generator to generate electricity, and the power battery outputs power at the same time, the P1 generator and the power battery are simultaneously input to the P3 drive motor, and the P3 drive motor drives the wheels; wherein, when the vehicle is in a uniform speed state, the first series mode is selected, otherwise the second series mode is selected.

[0013] Furthermore, when the power battery charge falls below the left endpoint of the low-battery range, the engine enters a constantly on state, entering a power replenishment mode. When the power battery charge reaches SOC = 13% and the vehicle speed is less than 20 km / h, the engine shuts down. Furthermore, C1, C2, C3, and C4 are 10%, 20%, 50%, and 80%, respectively; V1 is 20-25 km / h, V2 is 40-50 km / h, and V3 is 70-80 km / h.

[0014] Compared with the prior art, the present invention has the following beneficial effects: The present invention sets multiple power ranges according to the different power levels of the power batteries. Different oil-electric control strategies are adopted in the corresponding vehicle speed ranges, whether the vehicle runs at a constant speed, and different driving conditions in different power ranges. This can optimize the NVH of the engine, especially at low speeds, and achieve pure electric driving as much as possible while ensuring fuel economy, improving the quietness and smoothness of the customer's ride, and providing a better driving experience. BRIEF DESCRIPTION OF THE DRAWINGS

[0015] Figure 1 This is a flow chart of a method for controlling the oil and electricity of a single-speed series-parallel hybrid vehicle according to the present invention; Figure 2 This is a schematic diagram of energy distribution in the pure electric mode of the present invention; Figure 3 This is a schematic diagram of energy distribution in the engine direct drive power generation mode of the present invention; Figure 4 This is a schematic diagram of energy distribution in the direct drive mode of the engine of the present invention; Figure 5 This is a schematic diagram of energy distribution in the parallel mode of the present invention; Figure 6 Schematic diagram of energy distribution in the energy recovery mode of the present invention; Figure 7 This is a schematic diagram of energy distribution in the first series mode of the present invention; Figure 8 This is a schematic diagram of energy distribution in the second series mode of the present invention; Figure 9 This is the universal characteristic diagram of the engine of the present invention. DETAILED DESCRIPTION

[0016] The present invention is further described below with reference to specific embodiments. The accompanying drawings are for illustrative purposes only and are schematic, not actual, representations. They should not be construed as limiting this patent. To better illustrate the embodiments of the present invention, some components in the drawings may be omitted, enlarged, or reduced, and do not represent the actual dimensions of the product. It is understandable to those skilled in the art that some well-known structures and their descriptions may be omitted from the drawings.

[0017] The same or similar numbers in the drawings of the embodiments of the present invention correspond to the same or similar parts; in the description of the present invention, it should be understood that if the terms "upper", "lower", "left", "right" and the like indicate directions or positional relationships based on the directions or positional relationships shown in the drawings, it is only for the convenience of describing the present invention and simplifying the description, and does not indicate or imply that the device or element referred to must have a specific direction, be constructed and operated in a specific direction. Therefore, the terms describing the positional relationship in the drawings are only used for illustrative purposes and cannot be understood as limiting this patent. For ordinary technicians in this field, the specific meanings of the above terms can be understood according to specific circumstances.

[0018] Example 1 like Figures 1 to 6 The first embodiment of the present invention is a method for controlling the electric-hybrid powertrain of a single-speed series-parallel hybrid vehicle, comprising the following steps: S1. The vehicle's power battery capacity is divided into a low capacity range C1≤SOC<C2, a medium capacity range C2≤SOC<C3, a medium-high capacity range C3≤SOC<C4, and a high capacity range SOC≥C4; among which, C4 C3= C3 C2>C1; S2. Divide the vehicle's driving conditions into an accelerator-pressed state and an accelerator-released state; S3. The vehicle speed is divided into low speed V1, medium speed V2, and medium-high speed V3, and several speed intervals are obtained accordingly; among which, V3 V2>V2 V1; S4. Get the current running state of the vehicle; wherein the running state includes a uniform speed state and a non-uniform speed state; S5. Select a corresponding working mode based on the vehicle's current power range, the corresponding driving conditions, speed range and operating status within the power range, and determine the vehicle's current energy distribution through the corresponding working mode; wherein the working modes include: pure electric mode, engine direct drive power generation mode, engine direct drive mode, parallel mode, series mode, energy recovery mode, and non-energy recovery mode.

[0019] The present invention sets multiple power ranges based on the power battery's charge level. Different fuel-electric control strategies are employed in response to the corresponding vehicle speed ranges, whether the vehicle is operating at a constant speed, and different driving conditions. This optimizes engine NVH, achieving pure electric driving as much as possible, especially at low speeds, while ensuring fuel economy, enhancing the quietness and smoothness of the ride, and providing a better driving experience. The present invention can be applied to plug-in hybrid electric vehicles.

[0020] Among them, the power system of a single-speed series-parallel hybrid vehicle includes: an engine, a hybrid transmission, a power battery, and wheels. Among them, the hybrid transmission includes a P1 generator, a single-speed direct drive mechanism, and a P3 drive motor. There is mechanical transmission between the engine and the P1 generator, and a clutch is connected between the engine and the single-speed direct drive mechanism. The single-speed direct drive mechanism and the P3 drive motor are both mechanically transmitted to the wheels. The power battery is electrically connected to the P1 generator and the P3 drive motor, and the P3 drive motor is electrically connected to the P1 generator.

[0021] like Figure 2 As shown, the pure electric mode is: the power battery outputs power to the P3 drive motor, and the P3 drive motor drives the wheels; Figure 3 As shown, the engine direct drive power generation mode is: part of the engine power drives the wheels through the single-speed direct drive mechanism, and part of the power drives the P1 generator to generate electricity, which is then input into the power battery; Figure 4 As shown, the engine direct drive mode is: the engine drives the wheels through a single-speed direct drive mechanism; Figure 5 As shown, the parallel mode is: the engine drives the wheels through a single-speed direct drive mechanism, and at the same time the power battery outputs power to the P3 drive motor, which also drives the wheels; Figure 6 As shown, the energy recovery mode is: when the vehicle is coasting or braking, P3 drives the motor to generate electricity, which is then input into the power battery.

[0022] Example 2 This embodiment is a second embodiment of a method for controlling the oil and electricity of a single-speed series-parallel hybrid vehicle. This embodiment is similar to the first embodiment, except that the series mode includes a first series mode and a second series mode. Figure 7 As shown, the first series mode is: the engine drives the P1 generator to generate electricity, the P1 generator inputs to the P3 drive motor, and the P3 drive motor drives the wheels; Figure 8 As shown, the second series mode is: the engine drives the P1 generator to generate electricity, and the power battery outputs power at the same time. The P1 generator and the power battery are simultaneously input to the P3 drive motor, and the P3 drive motor drives the wheels.

[0023] According to Figure 9 The known engine universal characteristic diagram is shown, and the speed and torque corresponding to the point with the best fuel economy are selected. According to the formula P=n T / 9550, calculate the power Pe1 for optimal fuel economy, Pe1(i) refers to the output power of the engine for optimal fuel economy when the vehicle speed is i, such as Pe1(100) refers to the output power of the engine for optimal fuel economy when the vehicle speed is 100 km / h. According to the speed ratio of the single-speed hybrid transmission, the gear shifting smoothness can be guaranteed, and the direct drive vehicle speed and engine speed can be calculated. At the same time, if the speed is less than the direct drive speed, it is a series mode, and the speeds during series and direct drive shifts are close. For example, if the vehicle speed is ≥70 km / h, it is a direct drive mode, where the engine speed is 1550 rpm when the vehicle speed is 70 km / h. If the vehicle speed is less than 70 km / h, it is a series mode, where the vehicle speed is close to 70 km / h and the engine speed is 1500 rpm. It should be noted that the speed ratio of the single-speed hybrid transmission can be calculated using existing calculation methods.

[0024] Based on the vehicle's resistance parameters, the power of external loads such as low-voltage electrical appliances and air conditioners, and the transmission efficiency of direct drive and series connection, the engine power Pe2 when the vehicle is traveling at a constant speed can be calculated. Pe2(i) refers to the engine output power required to meet the vehicle's constant speed when the vehicle speed is i. For example, Pe2(100) refers to the engine power required to meet the vehicle's constant speed when the vehicle speed is 100 km / h. It should be noted that at the same vehicle speed, Pe1(i)>Pe2(i), and the engine's VNH at Pe1 is better than its VNH at Pe2. It should be noted that the power of low-voltage electrical appliances and air conditioners, and the transmission efficiency of direct drive and series connection can all be calculated using existing calculation methods.

[0025] exist Figure 9 In the chart, b represents the engine fuel consumption rate, which refers to the amount of fuel consumed by the engine under unit effective power output, and the unit is "grams per kilowatt-hour (g / kW-h)". On the same circle, the engine fuel consumption rate is the same. The closer to the inner circle, the smaller the value, and the lower the fuel consumption; that is, b1>b2>b3>b4>b5>b6>b7.

[0026] When the vehicle power is Pv, the battery power in the charging state is (-Pb), and the battery power in the discharging state is (+Pb), the vehicle power Pv in different working modes is: When the working mode is pure electric mode, Pv=(+Pb); When the working mode is engine direct drive power generation mode, Pv=Pe1+(-Pb); When the working mode is engine direct drive mode, Pv=Pe2; When the working mode is parallel mode, Pv=Pe1+(+Pb), or Pv=Pe2+(+Pb), which varies according to the current power range of the vehicle's power battery; When the working mode is the first series mode, Pv=Pe2; When the working mode is the second series mode, Pv=Pe2+(+Pb); When the working mode is energy recovery mode, Pv=(-Pb); When the working mode is non-energy recovery mode, Pv=0.

[0027] Therefore, based on the engine universal characteristic diagram and the above calculations, in this embodiment, C1, C2, C3, and C4 are selected as 10%, 20%, 50%, and 80%, respectively; V1 is selected as 20~25km / h, V2 is selected as 40~50km / h, and V3 is selected as 70~80km / h; preferably, V1 is 20km / h, V2 is 40km / h, and V3 is 70km / h.

[0028] Example 3 This embodiment is a third embodiment of a hybrid-electric control method for a single-speed series-parallel hybrid vehicle. This embodiment is similar to the first or second embodiment, except that, specifically, step S5 includes the following steps: S51. When the power battery power level is within the high power range, execute step S52; when the power battery power level is within the medium-high power range, execute step S53; when the power battery power level is within the medium power range, execute step S54; when the power battery power level is within the low power range, execute step S55; when the power battery power level is lower than the left endpoint of the low power range, execute step S56; Wherein, step S52 includes the following steps: S521. When the driving condition is the accelerator pedal, select the pure electric mode; when the driving condition is the accelerator pedal, execute step S522; S522. Set the high power interval C4≤SOC<C5, and set the extremely high power interval C5≤SOC<100%; preferably, C5 is 95%; then execute step S523; S523. When the power battery charge level is in the high range (80% ≤ SOC < 95%), select the energy recovery mode. When the power battery charge level is in the extremely high range (95% ≤ SOC < 100%), select the non-energy recovery mode.

[0029] It should be noted that in step S52, when the power battery power is in the high power range, there is no need to consider the vehicle speed range or operating status, that is, when the vehicle speed is at full speed, whether it is in a uniform speed state, or in an accelerating or climbing state in a non-uniform speed state, the working mode is selected in the manner of step S52.

[0030] Wherein, step S53 includes the following steps: S531. When the driving condition is a release throttle condition, the energy recovery mode is selected at all vehicle speeds and in any operating state; when the driving condition is a press-throttle condition, step S532 is executed; S532. When the vehicle speed is less than 70 km / h, in any operating state, the pure electric mode is selected; when the vehicle speed is ≥ 70 km / h, execute step S533; S533. When in a uniform speed state, select the engine direct drive mode; when in a non-uniform speed state, select the parallel mode. At this time, Pv=Pe2+(+Pb), which can ensure NVH when the engine is started.

[0031] Wherein, step S54 includes the following steps: S541. When the driving condition is a release throttle condition, at full vehicle speed, in any operating state, the energy recovery mode is selected; when the driving condition is a press-on throttle condition, step S542 is executed; S542. When the vehicle speed is less than 40 km / h, in any operating state, select pure electric mode. When the vehicle speed is in the speed range [40 km / h, 70 km / h), execute step S543. When the vehicle speed is ≥ 70 km / h, execute step S544. S543. When the vehicle is at a constant speed, select the first series mode; when the vehicle is at a non-uniform speed, select the second series mode; S544. When the vehicle is moving at a constant speed, select the engine direct drive mode. When the vehicle is moving at a non-uniform speed, select the parallel mode. In this case, Pv = Pe2 + (+Pb), which ensures NVH during engine startup.

[0032] Wherein, step S55 includes the following steps: S551. When the driving condition is a loose throttle condition, at full vehicle speed, in any operating state, the energy recovery mode is selected; when the driving condition is a throttle condition, step S552 is executed; S552. When the vehicle speed is less than 20 km / h, select pure electric mode in any operating state. When the vehicle speed is in the speed range [20 km / h, 70 km / h), execute step S553. When the vehicle speed is ≥ 70 km / h, execute step S554. S553. When the vehicle is at a constant speed, select the first series mode; when the vehicle is at a non-uniform speed, select the second series mode; S554. When the vehicle is moving at a constant speed, select the engine direct drive power generation mode. When the vehicle is moving at a non-uniform speed, select the parallel mode. In this case, Pv = Pe1 + (+Pb), which can slow the decline of the battery charge. The engine uses Pe1. Because tire noise and wind noise can partially mask the engine sound at speeds ≥ 70 km / h, VNH can be taken into account.

[0033] Among them, step S56 includes: at this time, the engine enters the normally-on state and enters the power replenishment mode; when the power battery is replenished to SOC=13% and the vehicle speed is less than 20km / h, the engine is shut down.

[0034] In the specific contents of the above-mentioned specific implementation methods, the various technical features can be combined in any non-contradictory manner. In order to make the description concise, not all possible combinations of the above-mentioned technical features are described. However, as long as there is no contradiction in the combination of these technical features, they should be considered to be within the scope of this specification.

[0035] Obviously, the above embodiments of the present invention are merely examples for the purpose of clearly illustrating the present invention, and are not intended to limit the embodiments of the present invention. Those skilled in the art will appreciate that other variations or modifications can be made based on the above description. It is not necessary and impossible to enumerate all embodiments here. Any modifications, equivalent substitutions, and improvements made within the spirit and principles of the present invention shall be included within the scope of protection of the claims of the present invention.

Claims

1. A method for controlling the oil and electricity of a single-speed series-parallel hybrid vehicle, characterized in that: The steps include: S1. Divide the vehicle's power battery capacity into a low-capacity range (C1≤SOC<C2), a medium-capacity range (C2≤SOC<C3), a medium-high-capacity range (C3≤SOC<C4), and a high-capacity range (SOC≥C4); Among them, C4 C3= C3 C2>C1; S2. Divide the vehicle's driving conditions into an accelerator-pressed state and an accelerator-released state; S3. The vehicle speed is divided into low speed V1, medium speed V2, and medium-high speed V3, and several speed intervals are obtained accordingly; among which, V3 V2>V2 V1; S4. Get the current running state of the vehicle; wherein the running state includes a uniform speed state and a non-uniform speed state; S5. Select a corresponding working mode based on the vehicle's current power range, the corresponding driving conditions, speed range and operating status within the power range, and determine the vehicle's current energy distribution through the corresponding working mode; wherein the working modes include: pure electric mode, engine direct drive power generation mode, engine direct drive mode, parallel mode, series mode, energy recovery mode, and non-energy recovery mode.

2. The oil-electric control method for a single-speed series-parallel hybrid vehicle according to claim 1, characterized in that: The power system of the single-speed series-parallel hybrid vehicle includes: an engine, a hybrid transmission, a power battery, and wheels, wherein the hybrid transmission includes a P1 generator, a single-speed direct drive mechanism, and a P3 drive motor; the engine and the P1 generator are connected by mechanical transmission, and a clutch is connected between the engine and the single-speed direct drive mechanism, and the single-speed direct drive mechanism and the P3 drive motor are both connected to the wheels by mechanical transmission; the power battery is electrically connected to the P1 generator and the P3 drive motor, and the P3 drive motor is electrically connected to the P1 generator.

3. The oil-electric control method for a single-speed series-parallel hybrid vehicle according to claim 2, characterized in that: In the pure electric mode, the power battery outputs power to the P3 drive motor, and the P3 drive motor drives the wheels; The engine direct drive power generation mode is as follows: part of the engine power drives the wheels through the single-speed direct drive mechanism, and part of the power drives the P1 generator to generate electricity, which is then input into the power battery; The engine direct drive mode is: the engine drives the wheels through the single-gear direct drive mechanism; The parallel mode is: the engine drives the wheels through the single-speed direct drive mechanism, and at the same time the power battery outputs power to the P3 drive motor, and the P3 drive motor also drives the wheels; The energy recovery mode is: when the vehicle is coasting or braking, the P3 drives the motor to generate electricity, which is then input into the power battery.

4. The oil-electric control method for a single-speed series-parallel hybrid vehicle according to any one of claims 1 to 3, characterized in that: In step S5, when the power battery power level is within the high power range: When the driving condition is to step on the accelerator, select the pure electric mode; When the driving condition is the throttle release condition, the energy recovery mode or the non-energy recovery mode is selected; among which: the high power range C4≤SOC<C5 is set; when the power battery power is within the high power range C4≤SOC<C5, the energy recovery mode is selected, otherwise the non-energy recovery mode is selected.

5. The oil-electric control method for a single-speed series-parallel hybrid vehicle according to any one of claims 1 to 3, characterized in that: In step S5, when the power battery power level is in the medium to high power range: When the driving condition is the throttle release condition, select the energy recovery mode; When the driving condition is the accelerator condition: when the vehicle speed is less than V3, select the pure electric mode; when the vehicle speed is greater than or equal to V3, select the engine direct drive mode or the parallel mode, among which: when the vehicle is in a constant speed state, select the engine direct drive mode, otherwise select the parallel mode.

6. The oil-electric control method for a single-speed series-parallel hybrid vehicle according to claim 3, characterized in that: In step S5, when the power battery power level is within the medium power range: When the driving condition is the throttle release condition, select the energy recovery mode; When the driving condition is the accelerator-pressing condition: when the vehicle speed is less than V2, select the pure electric mode; when the vehicle speed is in the speed range [V2, V3), select the series mode; when the vehicle speed is ≥ V3, select the engine direct drive mode or the parallel mode, among which: when the vehicle is in a constant speed state, select the engine direct drive mode, otherwise select the parallel mode.

7. The oil-electric control method for a single-speed series-parallel hybrid vehicle according to claim 3, characterized in that: In step S5, when the power battery power level is in the low power range: When the driving condition is the throttle release condition, select the energy recovery mode; When the driving condition is the accelerator-pressing condition: when the vehicle speed is less than V1, the pure electric mode is selected; when the vehicle speed is in the speed range [V1, V3), the series mode is selected; when the vehicle speed is ≥ V3, the engine direct drive power generation mode or the parallel mode is selected, among which: when the vehicle is in a constant speed state, the engine direct drive power generation mode is selected, otherwise the parallel mode is selected.

8. The oil-electric control method for a single-speed series-parallel hybrid vehicle according to claim 6 or 7, characterized in that: The series mode includes a first series mode and a second series mode. The first series mode is: the engine drives the P1 generator to generate electricity, the P1 generator is input to the P3 drive motor, and the P3 drive motor drives the wheels; the second series mode is: the engine drives the P1 generator to generate electricity, and the power battery outputs power at the same time, the P1 generator and the power battery are simultaneously input to the P3 drive motor, and the P3 drive motor drives the wheels; wherein, when the vehicle is in a uniform speed state, the first series mode is selected, otherwise the second series mode is selected.

9. The oil-electric control method for a single-speed series-parallel hybrid vehicle according to claim 3, characterized in that: When the power battery power is lower than the left endpoint value of the low power range, the engine enters the normal start state and enters the power replenishment mode; when the power battery power is replenished to SOC=13% and the vehicle speed is less than 20km / h, the engine stops.

10. The oil-electric control method for a single-speed series-parallel hybrid vehicle according to any one of claims 1 to 3, characterized in that: C1, C2, C3 and C4 are 10%, 20%, 50% and 80% respectively; V1 is 20~25km / h, V2 is 40~50km / h and V3 is 70~80km / h.

Images